1. Field of the Invention
The present invention relates to a gas generator using a solid gas generating agent and being employed to a restraining device for a vehicle or the like.
2. Description of Related Arts
Gas generators for use in restraining devices such as an airbag apparatus can be of a pyrotechnic gas generator using a solid gas generating agent, a stored gas generator using pressurized gas, and a hybrid gas generator using both of the above. Among these, in a pyrotechnic gas generator, which is advantageous from the standpoint of weight reduction, the surface area of the gas generating agent is strictly controlled to exhibit ignition and combustion of the gas generating agent with good reproducibility.
When a gas generator is assembled or transported, impacts caused by vibrations or the like are applied thereto. In addition, the gas generator installed on a vehicle is constantly subjected to vibrations as the vehicle travels. Therefore, where a solid gas generating agent is gradually powdered under the effect of the impacts and vibrations and the surface area of the gas generating agent increases, the combustion performance thereof changes. In order to avoid these changes, a cushion is disposed inside the combustion chamber to relax the impacts applied to the gas generating agent. An elastic cushion is usually used, and specifications (thickness, number of sheets, etc.) thereof are changed according to the amount of the gas generating agent to be loaded into the combustion chamber.
U.S. Pat. No. 5,625,164 discloses a configuration in which an annular cushion 120 is disposed on a disk-shaped gas generating agent 110. The cushion 120 is disposed in an elastically deformed state between a canister cover 78 and an uppermost disk 110U. Prior to the installation, the cushion 120 has a tapered shape, as shown in FIG. 3. Once installed, the cushion is attached in a state in which the cushion is bent in a bent portion 134 as shown in FIG. 2 and that the thickness in the direction of an axis 40 thereof is decreased.
In U.S. Pat. No. 5,625,164, the cushion 120 is a separate member that is disposed inside the canister after the gas generating agent 110 has been loaded during the assembling operation. However, the orientation of the cushion during assembling can be confused, it is possible to forget to assemble the cushion, and the cushion can be dislocated during the assembling operation.